Refrigerating apparatus



June 30, 1959 R. W. KRITZER REFRIGERATING APPARATUS Filed Jan. 13, 1956{IDEDEJCQDE @QDEDGEE) E) :sucked from the evaporator into the condenser.reduces the flow to the compressor and prevents circu- I lation of therefrigerant through the evaporator for ader quate cooling.

United States Patent REFRIGERATING APPARATUS Richard W. Kritzer,Chic'ago, 111. Application January 13, 1956, Serial No. 558,891

8 Claims. 01. 62-196 The invention relates to refrigerating apparatus ofthe type in which the condenser for the refrigerant is subjected tooutside air and a cooling unit or evaporator is disposed inside of thebuilding.

In apparatus of this type, unusually low temperatures during coldweather sometimes cause the refrigerant tolbe T is One object of theinvention is to provide equipment which will insure circulation of therefrigerant during severe temperature-drops in the condenser when it issubjected to outside air.

Another object of the invention is to provide means for .boosting thepressure of the refrigerant in the condenser "to reduce the load on thecompressor and to economize in the consumption of power.

Other objects of the invention will appear from the detail description.

The invention consists in the several novel features lhereinafter setforth and more particularly defined by claims at the conclusion hereof.

In the drawings:

.Fig. 1 is a vertical section, parts being shown in elevation, ofrefrigerating and cooling apparatus embodying :the invention; and

Fig. 2 is a diagrammatic view of the electrical circuits z'for thecompressor-motor, the valve for by-passing the irefrigerant around thecompressor, and the valve for (closing the conduit between therefrigerant-pump and the :condenser-coils.

lIhe invention is exemplified in apparatus which comprises: arefrigerating unit which is mounted on the roof or outside of a buildingand includes a compressor, a

iliquid-receiver and a condenser; and an air cooling or rconditioningunit which is mounted inside of the building and includes an evaporatorand an air impeller. As the result of this disposition of these unitsoutside and inside tof the building during different seasons of theyear, the refrigerant in the condenser is subjected to wide changes oftemperatures relatively to the temperature of the re- :frigerant in theevaporator. For example, the cooling temperature of refrigerant in theevaporator may range :from 32 to 40 F. with a pressure of 30 to 40 lbs.p.s.i., while as the result of a temperature drop caused by Weatherchanges, for example to 24 F., the temperature :of the refrigerant inthe condenser-coils will drop below athe temperature in the evaporatorso that the refrigerant the evaporator will be sucked into the condenserwhich renders the compressor ineffective to adequately circulate therefrigerant through the evaporator for the desired tCOOIlHg. The presentinvention includes a pump for conztinuing the feed of refrigerant to theevaporator notwithstanding the changes in pressure in the refrigeranttin-the condenser-coils from weather conditions in connecuion with aby-pass conduit for the refrigerant around the compressor and from theevaporator to the condensercoils and also for utilizing the pump toeconomize the work of the compressor.

The invention is exemplified in refrigerating apparatus which comprises:a combined electric-motor and compressor unit 20 for the refrigerant; acondenser including heat exchange coils 21 and an air impeller 22 drivenby an electric-motor 23, all disposed in a suitable casing or housing 24mounted on the roof 25 of a building Where outside air is available; anda cooling unit which is disposed inside of the building and comprises:an evaporator 26 including finned coils and an air impeller 27 driven byan electric-motor 28 and are all mounted in a casing or housing 29disposed inside of the building. The impeller is supported in a frame29a in casing 29. The casing 24 is secured on a plate 30 which fits overa curb 31 around an opening 33 in the roof 25 and has affixed thereto apendant section of tubing 34. The casing 29 is secured to an upstandingtube-section 35 which fits telescopically in the tube 34 and isadjustably secured therein by one or more set-screws 36. The highpressure side of the compressor is connected by a conduit 40 to theinletheader 41 for the condenser coils 21. The outlet-header 42 forcoils 21 is connected by a conduit 43 to deliver refrigerant into theliquid-receiver 44. 'I'he low pressure side of the compressor of unit 20is connected by a conduit 45 to the outlet-header 46 of the coils ofevaporator 26. The inlet-header 47 for the coils of evaporator 26 isconnected by a conduit 48 to the outlet side of a rotary pump 50 whichhas its inlet side connected by a conduit 51 to the 'bottom of. thereceiver. An expansion valve 49 is included in conduit 48. Rotary pump50 is driven by a pulley 52 on the shaft of motor 23, a pulley 53 on theshaft of said pump and a V-belt 54 between said pulleys. Pump 50 has itsintake conduit 51 leading from the bottom of receiver 44 and itsdischarge side is connected to conduit 48 which is connected to theinletheader 47 of the evaporator-coil. A conduit 59 between thedischarge side of pump 50 and the inlet-header41 of the condenserincludes a thermostatically controlled valve 58 which, when open,permits pump 50 to force via conduit 59 some of the refrigerant fromreceiver 44 into the inlet-header 41 for the coils of the condenser 21.When valve 72 is open and pump 50 and the compressor are both operated,the pressures of refrigerant forced by pump 50 and by the compressorinto the inlet header 41 are cumulative in the condenser. When valve58'is closed and the compressor is idle, pump 50 is adapted to forcerefrigerant from receiver 44 via pipe 48 to the evaporator. Conduits 45and 48 extend through the tubular sections 34 and 35 which supportcasing 29 and are provided with flexible coils which permit verticaladjustment of the cooling-unit without disconnection from therefrigerant conduits 48 and 45. A thermostatically controlled valvegenerally designated 60 is included in a by-pass conduit 61 betweensuction-conduit 45 and high pressure conduit 40 for controlling theby-pass of refrigerant around the compressor, from the evaporator to thecondenser coils 21. When valve 60 is closed, the compressor will drawrefrigerant from the evaporator and under pressure force it via conduit40 into the condenser-coils 21. When valve 69 is open and the compressoris idle, the refrigerant can by-pass the compressor and flow fromevaporator 26 via header 46, conduit 45, conduit 61 in which valve 60 isincluded, conduit 40 and header 41 into the coils of condenser 21. Whenvalve 60 is closed and valve 58 is open, the compressor can circulaterefrigerant from the outlet header 46 of evaporator 26 via conduit 45,the compressor of unit 20, conduit 40, header 41, the'coils of condenser21, header 42 and conduit 43 to the receiver 44. Pump 50 will beoperative to circulate the refrigerant from receiver 44 and conduit 51through the coil of evaporator 26 via conduit '48 and expansion valve49, and also to force some of the refrigerant from the receiver 44 viaconduit 59 and header 41 to exert pressure on the refrigerant in thecondenser-coil.

--2 diagrammatically illustrates the circuits and switches: for normallyclosing'v'a lve 66 and permitting refrigerant to circulate from theevaporator via conduit 45,-'the compressor and conduit 41, to'con'denser21; for openingnvalvefitll to permit the pump 59 to circulate therefrigerant (valve .58 .beingiclosed) from condenser 21, via' conduit.43, .receiver 44, conduit 51, pump .50, conduit 48, evaporator"26,conduits 45 and 61, valve 60 (then open), conduit 4%, to condenser 21and conduit 43 which communicates with the receiver; fonclosing valve 58when ,the by-p as s valve 61 is open, and openingvalve 58 (valveoo'.being closed) to cause pump-.50 to..-boost'..the.pressure on therefrigerant"in conduit' 59 and the condenser. The valve 58 includes asolenoid magnet 71 with a normally open valve member .72. 'The valve 60includes a solenoid mag- .net 76 and a normally closed member 77. Themagnets .-71 and ..76 are connected in series to a switch 73 controlled?by a thermostat 75 responsive, to outside temperature. .Switch 73 isconnected to line-conductors 78 '.and.:79. .The motor of thecompressor-unit is controlled -by a 'thermostat82 responsive to outsidetemperature. .Additionally said motor may also be thermostatically.coiitrolledfas.Iwellunderstood in the art, for automaticallystartihgand stopping the compressor responsive to -the .temperature of the aircooled by the evaporator. :iwhenthermostat 75 closes switch 73, magnet71 will be energized to close valve-member 72 and magnet 76 will beenergized to open valve-member 77. When the mag- .netsUl and 76, are all.deenergized, valve-member 72 of :,-valve 5.8.willbeopen .and member 77of valve 60 will ,helclosed.

The operationwillbe .as follows: the apparatus may :bqdesigned toproduce a head-pressurein the condenser of 3Q to 6.0 lbs.. p.s.i. whilethe temperature of the outside air around the condenser. remains above35F. and .thecirculationpfthe refrigerant between the evaporator and thecontilenser.byflthe compressor to'm'aintain the desiredjrange of coolingIaround the evaporator, in re- ,spo ns e to usualautomatic thermostaticcontrol for the cgmpressor unit (not shown) Under these conditions,thermostat 82 which responds to the temperature of outside-air willclose its associated switch and keep the compressor-motor in operation.Thermostat 75, also responsive to the temperature of the outside air,will in- .,ter i upt-.the circuit'through solenoid magnets 71 and 76 sothatvalve 72 will remain openand valve 77 will renain closed. iTherefrigerant will then be circulated as -,f Ql19ltV S: from thepressurerside. of the compressor of unit :3 Qq d iswii llct hcader 41 ofcondenser 21; conduit 43; reeeiver A4; conduit ,51; pump .50; conduit48; ex- 129 1 .y lve 5, ead 47', he coils and header 4s of 3, orator-26;andiconduits ,46 and 47, to the suction side of; said, compressor. Therefrigerant will be condensed yvhenitpasses intoreceiver 44 andahead-pressure of t e; refrigerant inthe condenser will be maintainedbe- .;..tween 3010 160 lbs. p.s.i. in the condenser and therefrigerantwill-be circulated to cool the evaporator as desired.The.Iiefrigerantinthe condenser will be under head- "pressure tocirculate in the system and cool'the inside air o'f.-normal temperatureimpelled through inside casing 29." -Refrigera'nt from the outlet ofpump 59 will also pass through valve58, which is open, and conduit 59,to

merge at'conduit 40 with therefrigerant passing to the 1' condenserfromthe compressor, to boost the pressure of thepijefrigerant .in thecondenser. This acts against the 1 :1ead-p ress ure of the refrigerantin the condenser which {may at timeshbeaswhigh as 150 lbs. p.s.iLandrelieves l or. .nn wsnhe lpad' ,on the motor of the compressor- 4 unit.This results in economical operation of the cornpressor-motor.

If the temperature of the outside air impelled through casing 24 andcondenser 21 drops to sub-normal, for example, to about or below 24 F.,the pressure of the refrigerant in the condenser drops to 0 to 5 lbs.p.s.i. while the inside air around the evaporator may produce a pressureof 30 to 40 lbs. p.s.i. in the evaporator. These differentials inpressure will then cause the refrigerant from the evaporator to remainor be sucked into the condenser so that the compressor will not causethe refrigerant to flow from the evaporator to the condenser. Thisimpairs or prevents the evaporator from performing its cooling functionas desired.

For maintaining flow of the refrigerant from the condenser to theevaporator uponthis drop in head-pressure in the condenser as aforesaid,the thermostat 82 which is responsive to the temperature below, forexample 35 F., will open the electric circuit for and stop the motor ofthe compressor unit, and thermostat 75 closes switch 73 for energizingthe electro-magnet 71 to close valve 58 and energizes magnet'76 toopenvalve 60. Thermostats S2 and 75 may be actuated in response, forexample, to an outside temperature'of about 30 to 35 F. or before theresultant drop in pressure in the condenser is sufiicient to cau'setherefrigerant to be retained in the condenser. Pump 50 will continue tocirculatethe refrigerant from the receiver 44 via'conduitssl and 48; theinlet header 47, coils and outlet header 46 of evaporator 26; conduit45; valve 60; conduits 61 and 40; the inlet header 41, the coils'and'outlet header-42' of condenser 21 and conduit 43, to the'receiver44. 'Asa result, the differential pressures in the condenser 21-aridevaporator will not stop the circulation of'r'efrigerant be- .tween theevaporator and the condenser. This will continue until the compressor isagain started in response to an increase of the temperature of theoutside air to its normal'range. The invention is not to be understoodas restricted to the details set forth, since these may be modifiedwithin the scope of the appended claims without departing from thespirit and scope of the inventron.

Having thus described the invention what I claim as new and desire tosecure by Letters Patent is:

l. The combination of refrigerating apparatus including a motor-drivencompressor and an air cooled condenser-coil connected to receiverefrigerant from the compressor and mounted outside of a'building whereit is subjected to outside air; apparatus mounted in and for cooling airinside of the building, including an evaporator connected to receiverefrigerant from the'condens'er-coil and to the suction side of thecompressor; temperature controlled means for'by-passing the refrigerantfromthe evaporator around the compressor and to'the condensercoils; apump for forcing condensed refrigerant't'o the evaporator; and a conduitfor refrigerant from the'pump to the condenser-coils.

2. The combination of refrigerating apparatus including a motor-drivencompressor and an air-cooled condenser-coil connected to receiverefrigerant from the compressor and mounted outside of a building whereit is subjected to outside air; apparatus mounted in and for cooling airinside of the building, including an evaporator connected to receiverefrigerant from the condensercoil and to the suction side of thecompressorytem'peratur'e controlled means for by-passing the refrigerantfrom the evaporator around the compressor and 'to the condenser-coils;and a pump for forcing condensed refrige'rant to the evaporator; andthermostatically controlled means for forcing refrigerant from the pumpto the condenser-coils.

3. The combination of refrigerating apparatus including a motor-drivencompressor, an air-cooled'condens'ercoil mounted on the outside'of abuilding where it is subjected to outsideair and connected toreceive'refrigerant from the compressor, a liquid-receiver connected toreceive refrigerant from the condenser-coil; air-cooling apparatusmounted inside of the building and including an evaporator connected tothe suction side of the compressor, a pump connected to forcerefrigerant from the receiver to the evaporator, a conduit for the flowof some of the refrigerant from the pump into the condensercoil; athermostatically controlled valve for controlling said conduit; and aconduit for by-passing refrigerant from the evaporator to the condenserand around the compressor.

4. The combination of refrigerating apparatus including a motor-drivencompressor, an air-cooled condensercoil mounted on the outside of abuilding Where it is subjected to outside air and connected to receiverefrigerant from the compressor, a liquid-receiver connected to receiverefrigerant from the condenser-coil; air-cooling apparatus mountedinside of the building and including an evaporator connected to thesuction side of the compressor, a pump connected to force refrigerantfrom the receiver to the evaporator, a conduit for the flow of some ofthe refrigerant from the pump into the condenser-coil; athermostatically controlled valve for controlling said conduit; aconduit for by-passing refrigerant from the evaporator to the condenserand around the compressor; and thermostatically controlled means forcontrolling the by-pass.

5. The combination of a refrigerating unit comprising a motor-drivencompressor, a condenser coil, a conduit for refrigerant from thepressure side of the compressor to the condenser coil, a motor-drivenimpeller for circulating air around said coil, and a casing disposed onthe outside of a building, provided with openings for the flow ofoutside air therethrough and in which said condenser-coil, impeller andcompressor are mounted and an air-cooling unit comprising an evaporatorconnected to the suction side of the compressor, a casing inside of thebuilding enclosing the evaporator, provided with openings for the flowof inside air therethrough; a liquid receiver connected to receiverefrigerant from the condenser coil; a pump connected to forcerefrigerant from the receiver to the evaporator; a conduit fordelivering some of the refrigerant from the pump into thecondenser-coil; a temperature-controlled valve for cutting ofi flowthrough said conduit; and a by-pass for refrigerant, around thecompressor, from the evaporator to the condenser, provided with atemperature-controlled valve for controlling the by-pass.

6. The combination of a refrigerating unit comprising a motor-drivencompressor, a condenser-coil, a conduit for refrigerant from thepressure side of the compressor to the condenser-coil, a motor-drivenimpeller for air around said coil, and a casing disposed on the outsideof a building provided with openings for the flow of outside airtherethrough and in which said condensercoil, impeller and compressorare mounted, and an aircooling unit comprising an evaporator connectedto the suction side of the compressor, a motor-driven impeller for airaround the evaporator, a casing inside of the building enclosing theevaporator and last named impeller, provided with openings for the flowof inside air therethrough; a liquid receiver connected to receiverefrigerant from the condenser coil; a pump connected to forcerefrigerant from the receiver to the evaporator; a conduit fordelivering some of the refrigerant from the pump into the condensercoil; a temperature-controlled valve for cutting off flow through saidconduit; and a bypass for refrigerant around the compressor from theevaporator to the condenser, provided with a temperature controlledvalve for controlling the by-pass.

7. The combination of refrigerating apparatus including a motor-drivencompressor and an air cooled condenser-coil connected to receiverefrigerant directly from the compressor and mounted outside of abuilding where it is subjected to outside air and temperature controlledmeans responsive to said outside air for controlling said compressor;apparatus mounted in and for cooling air inside of the building,including a receiver for the condensed refrigerant, an evaporatorconnected to receive refrigerant from the condenser-coil and to thesuction side of the compressor; temperature controlled means forby-passing the refrigerant from the evaporator around the compressor andto the condenser; and a pump connected to force condensed refrigerantfrom the receiver to the evaporator and merge it with the refrigerantpassing from the compressor to the condenser during the simultaneousoperation of the compressor and pump for cumulating pressures ofrefrigerant from the pump and compressor in the condenser.

8. The combination of refrigerating apparatus including a motor-drivencompressor, an air-cooled condensercoil mounted on the outside of abuilding where it is subjected to outside air and temperature-controlledmeans responsive to said outside air for controlling said compressor andconnected to receive refrigerant directly from the pressure side of thecompressor, a liquid-receiver conneoted to receive refrigerant from thecondenser-coil; air-cooling apparatus mounted inside of the building andincluding an evaporator connected to the suction side of the compressor;a pump connected to force refrigerant from the receiver to merge withthe refrigerant from the compressor in the condenser coil and boostingthe head-pressure when the compressor and pump are simultaneouslyoperated, temperature-controlled means for controlling the flow ofrefrigerant from the pump to the condenser, and temperature-controlledmeans for bypassing refrigerant from the evaporator around thecompressor to the condenser when the compressor is idle.

References Cited in the file of this patent UNITED STATES PATENTS2,165,741 Wolfert July 11, 1939 2,244,312 Newton June 3, 1941 2,286,961Hanson June 16, 1942 2,718,766 Imperatore Sept. 27, 1955

